Bus transfer



Feb. 20, 1945. F, Q |G| EHART ETAL 2,370,039

BUS TRANSFER @wg WM5-BMM I v AWORNEY Feb. 20, 1945. F. c. IGLEHART ETAL BUS TRANSFER Fild Dec. 3l, 1941 3 SheebS-Shet 2 d MM. www n NdH N EM R w/a m lfaw. T @L A 0 am n/B, .m 2. m M 9 -Il Fe @o WITNESSES: M2 MM Feb. 20, 1945. F c |G| EHART ETAL 2,370,039

BUS TRANSFER Filed Deb. 31, 1941 3 sheets-sheer s Patented Feb. 20, 1945 BUS `TRANSFER Ferdinand C. Iglehart, Wilknsburg, and Bruno L.'Ullrich, Forest Hills, Pa., assignors to Westinghouse Electric & Manufacturing Company,

- East Pittsburgh, Pa., a 'corporation of Pennsylvania .i

Application December 31, 1941, Serial No. 425,156

15 Aclaimsl ,(01. 20o- 5) rf'his invention relates to a bus transfer and, more particularly, to an emergency operating means for a bus transfer having electrical means: for operating the'same.

Bus transfers are commonly used for changing the connections of an electric load, such as an electric motor, from one source of current to another. To accomplish this, there` may be provided a pair of switches respectively connected` to a set of bus bars and movable to closed position for selectively connecting the load to such bus bars, together with latches which are movable by appropriate means to locking vposition for,

holding the switch in closed position upon movement of the switch to such position. Since it would be obviously undesirable to connect the electric load to both sets of bus bars at the same time, interlocks are provided for preventing simultaneous closure of the switches.'

In such bus transfers, the actuation of the switches and their associated latches is effected through power means such as electromagnets having suitable operating connections with the electric switches and associated latches. The control for the power operating means or electromagnets is commonly located at a point remote `from the bus transfer itself. y Occasions frequently arise, due to failure of the electrical control, or for other reasons, when it is desirable to operate the bus transfer manually at its place of location. operating means for the bus transfer is particularly desirable on equipment such as naval equipmentwherein the control station is likely to be put out of commission and emergency. means for operating the bus transfer mustvbej immediately available.

One of the principal objects of this invention- A further object is to provide, in a bus trans-` fer having power means for operating the same an emergency operatingk meanstogether with an interlock :for rendering the powerA operating means inoperative upon operation of the emergency means. 1

A further objectof this invention is to provide` a bus transfer having power Vmeans for operate ing the same with an emergency operating meansv and an interlock which is actuable to render the Vpower means inoperative and the emergency means operative.

A further object is to provide, in a bus transfer rlhe provision of emergency having a pair of switches and power means controlling the loperation of such switches, an emergency mechanical means for `operating the switches comprising a manually operable lever movable in opposite directions from a neutral position to switch Yoperating positions for closing a selected one of the switches.

A further object is to provide an emergency bus transfer operating lever with interlock means effective to prevent operation of the lever during operation of the power means and actuable to render inoperative the power means and render operative the emergency lever.

Other objects and advantages of the invention will become apparent from the studyof the following description andaccompanying drawings,v in which:

Figure 1 is a plan view` of a bus transfer having emergency operating means constructed in accordance with the principles of this invention;`

Fig. 2 is a side elevational view of the mechanism shown in Fig. 1 f

Fig. 3 is a detailed sectional View taken substantially onthe line III--III of Fig. 1;

Fig. 4 is broken away view of a portion of the bus transfer casing through which the emergency operating handle extends, showing the manner in which the handle cooperates with indicia on the casing to indicate the condition ofthe switch contacts within the' casing; and

Fig. 5 is a sideelevational View similar to Fig. 2 showing afmodied arrangement of emergency operating means in connection with a different type of bus transfer.

Referring to the drawings, the numeral I0 designatesA a panel support having, an upper switch unit indicated as a whole by the letter A. and a lower switch unit indicated as a whole by the letter B mounted thereon. The switch units A and B are `provided `with suitable connections (not. sho-wn) tobus bars and electric load or' motor leads and are operable upon selected clo.- sure thereof 4to connect the loadleads to va set of bus Vbars in a manner well known in the art.

insulated shaft I2 or ||2 rotatably mounted in bearings I3 and |4 or ||3 and ||4. According to the direction of rotation imparted to the shaft I2 or I I2, the movable contacts will be moved either to or out of engagement with stationary contacts I5 or ||5 to open or close the switch. The movable contacts I\| and vmay be connected to the leads (not shown) of an electric load or motor and the stationary contacts I5 and I |5 may be connected with a set of bus bars (not shown) in a manner Well known in the art.

As best shown in Fig. 2, rotation is imparted to the shaft I2 or |12 by means of a :bracket member I6 or |I6 rigidly ,connected thereto. spring or is engagea-ble with the yruiter end I8 (I I8) of the bracket IB (l'IfB) and provides a bias tending tomove the bracket I6 (|15) in a counterclockwise direction. In this man-neit,

bias is provided which tends to move the .shaft I2 (|I2) and movable contacts II (III) out *ot engagement with the stationary contactors |.5 (I 1.5).. .In order to .move .the contacts (l I IZ) to vtheir closed position `against the 'bias of the spring y|''| (-||`1.), .a power-.operated .actuating means .isprovided consisting of .an electromagnetl I8 (-I I8.) with an armature 2D (1.20).. .'Iihecarmature is pivotally connected 'to links 12| (|2I.) which .are in turn pivota'lly lconnected to and support a lroller 22 (122 pon .movement vbeing imparted to 'the .armature 20 '('I2'0) the roller will be moved .in an larcuate path controlled by the radius of la link A23 (|23) which has one end pivotally connected to :the vroller '2'2 (I 212) .and its other 4end pivotally connected lat "2l (I2-4.) lto the .support ID `asbest shown Vin Fig. 4'2.

A latch 25 '(125) .is mounted .'forLp'ivo'tal move-- ment about a pivot 26 `(|26) to and rom v.positions locking its .associated vswitch against movement. .'IYhelatch is in the .nature of abell crank and a .spring 32'! (|21) is provided for .engagement with the outer end of one arm .28 (128) thereof. The spring 2I (|21) `,ygsrov'irzles .a bias tending .to move lthe bell crank 25 (|525) in a clockwise direction to its llocking position. 'The other arm-.29 (|29) of 'the bell crank v.is vprovid-eci with a ledge 30 (|30) for engagement with the roller 2'2 (|22) to hold the ybracket I6 I6) in a position vfor maintaining the shaft I2 (.II2) in a position with the movable contacts II '(III) in engagement with the stationary `contacts I5 In order to trip the latch 25 v(|25), an electromagnet 3| IBI) having its armature '32 "('I32) connected to the arm '28 "('I'28) by alink 33 (I3`3`) is provided. Upon energization .of the electromagnet the armature :and link will be drawn upwardly to move the latch in a .counterclockwise direction against the bias ofthe spring `2I (|21) Counterclockwise movement oi the latch ywill '.be effective to disengage the ledge 3'0 (|30) from the roller and permit the spring 'to move the bracket I6 (IIE) and associated Acontacts to the open position.

In the showing voi Rigs. 'and 2, the contacter' 35 (|735) to deene'rgize -vthe coil 'I9 5(1II 9.).

be rst energized to impart counterclockwise movement to its associated latch 25 to disengage roller 22 and permit opening of the unit A in the manner described above. Thereafter the electromagnet ||9 associated with the lower switch unit B will be energized to impart upward movement to its associated roller |22. A Icamming surface 34 '(134) .is provided on each bracket 22 which is engaged by its associated roller 22 in upward movement thereof, such up- Ward .movement being effective to move the bracket I6 clockwise against the bias of its spring.

'.'Iil'iesubsequent-energization of the electromagnet H19 associated 'with the unit B is thereby effective 'to 'fclose the #contacts of a switch unit B. After operation Jof the bracket IIB associated with the lower 'switch unit B to close the contacts `of "unit, 'the :latch |25 of the unit B will be moved b y the bias of its spring |21 in a countercioc'kwise direction to latch the bracket IIS in its closed 4position.

To insure the retention of the magnets I9 and .I-I-9-ln circuit only .long enough to close their associated contacts, stationary .and movable contacts-35, A."'ll and |25, |36, respectively, fare .included inthe circuit of .the electromagnets I9 and .'II`9. `As pointed `out above, closure of one of the contactors .results 'in clockwise movement of the latch 25 or .|25 by thespring i27| or |2'I. Such clockwise movement or the 'latch results in downward .movement of the link '33 (|33) and upon movement of the latch to its .locking position, an arm. -37| '(1351) .secured to the link engages 'with the movable contacter 3E (|36.) to disengage 'the contact 3`6 (|36) .from the contact The latch 25- ?(I'ZE) is thereafter'eiective to .maintain the associated .movable contacts -I I '(I I'I in their closed position. l

.'I'ofinsure the retention of the electromagnets 3| `and |3| .in .the circuit only long venough to ellectmovement of the .latches to unlocked position Vagainst Vthe 4bias oi the springs, stationary 'andmovablecontacts 3B, .39.'and |38, |39 (Fig. l)

- are `includ-ed .in `.the coil circuit of the electromagnetsl and 13|, respectively. I'Ihe movable contacts "39 (|39.) are .mounted on ythe shaft I2 (112.) .for rotation therewith, and upon movement of the shaft toa position disengaging the contacts Il (.I .I I) .from the .stationary contacts I5 (.I I5.).,.themovablecontacts39 (|39) will .be disengagedfrom .the 'station-ary contacts v3B (|38) and the coil circuit o'f the .electromagnet 3| A(ISH) will vbe deenergized.

'The emergency operating .system of Figs. l .and 2 .comprises a manually operable .lever 4D mounted for pivotal movement about a pivot 4| from the switch operating :position .shown in solid lines to the .switch operating .position shown in dot-and-dash lines. The .lever 4U .is provided with 'a pin and slot connection 42 to a member 43 mounted forrotatable movement about a pivot 44, the ,pin and slorJ connection 42 .enabling the transmission of lpivotalmmement of the lever 4B to the .member 43. rOpposite ends of the member 43 are .respectively provided with actuating links 4'5 'and .|45 pivotally .connected thereto. The outer end olf each link is provided with an elongated .slot 46 (|46) .through which la vportion 41 or |41 of the shaft on ,which .the/roller "22 or |22 is .mounted projects. Cooperation 'of the shaft portion 47 '(I4'I.) with 'the slot 46 (|146) -provides a .control 4for operationof the switch unit `contactors. 'The outer end '0i' each link rotatably supports a roller 43 (|48) which is engageable with a. comming surface 49 (|49) on latch member-25Y (|25). Cooperation of the roller 48 (|48) with the camming surface =49 (|49) effects a control actuation of the latch 25 (|25) in a manner to be described.

The solid and dot-and-dash lines showing the lever 40 in Fig. 2,` indicate the two extreme operating positions adapted to be occupied for such lever. In moving from the position shown in solid lines to the position shown in dot-and-dash lines, the lever 40 moves through three other positions approximately indicated by the center lines 50, and 52. The center line 5| indicates the Vposition which will be occupied by the operating lever 40 when in its neutral position and the center lines 50 and 52 indicate so-called tripping positions to be occupied by the lever 4D.

With the lever 40 in the position shown in full lines, the switch unit A is in its closed position with its associated latch in locked position and the switch unit B is in its open position with the latch |25 in its unlocked position.

Assuming that it is desired to open the switchl unit A and close the switch unit B, the lever is moved from the position shown in solid lines -to the position shown in dot-and-dash lines.v

During this movement, the lever 40 passes through the positionsindicated by the centerY place is a relative change in the position of the actuating links and |45 and their slots 46 and |46 relative to the roller parts 41 and |41. As the lever 40 moves from its neutral position to the tripping position indicated by the center line 52, the camming roller 4B on the upper link 45 moves into engagement, with the camming surface 49 and cams the latch 25 in a counterclockwise direction against the action of the spring 21 to trip the switch unit A and cause its bias as provided by the spring |1 to become eiiective for moving the switch unit A to open position. At about the time the switch unit A is tripped to open position. the lower end of the slot in the lower link |45 will have moved into engagement with the shaft portion |41. Thereafter, movement of the lever 4l) from the tripping position indicated by the center line 52 to its position as indicated in dot-and-dash lines will be effective to impart upward movement to the roller |22 of the switch unit B. Such upward movement of the roller will cam the member ||6 in a clockwise direction against the bias of its spring ||1 to close the movable contacts of the switch unit B.

It will be understoodthat the reverse of the above described movements will' take place upon movement of the lever 40 from the position shown .in dot-and-dash lines to the position shown in full lines to trip the switch B and close the switch A. In such case, the switch B will not trip until theV lever 40 moves into the tripping position as indicated by the center line 50.

The manner in which the lever 40 cooperates with the contactor B to indicate its various positions 'is best shown in Fig. 4. In this showing. the housing cover plate is indicated by the numeral |53 and is provided with an opening |54 through which the lever 40 projects. Indicia in the nature of descriptive matter is marked on the surface of the cover plate |53 to indicate, F

bycooperation with the handle 40, the condition of'the mechanism underneath the -cover plate |53. In this manner it is merely necessary for an operator to glance at the position of the lever 40 to know immediately which of the switch units have been closed or tripped.

An interlock system is `provided for preventing simultaneous operation of the automatic or power operating means and the emergency mechanical means. The interlock system. comprises a pair of latch plates 53 and 54 keyed to the pivot shaft 4| so as to be rotatable with the handle 4U. A pair of latching members 55 and 5S are mounted for pivotal movement and cooperate with the latch plates 53 and 54 in a manner to be described. Springs 51 provide a bias tending to move the latches 55 and 56 in a counterclockwise direction. A latch operating push button 58 projecting through the opening in the cover plate |53 is operable through an actuating member 59 to impart movement to the latch 56. The actuating member 59 engages with a member 6D on the. latch 56 for imparting pivotalmovement to such latch in a clockwise direction against the bias of its spring 51. 4The latch 55 is provided with a part 6| projecting outwardly over the latch 55, as viewed in Fig. l, whereby inward movement imparted to the latch 56 will `be effective to impart inward movement to the latch 55.

^ As best shown in Fig. 3, the latch plate 54 is provided with five notches 62 corresponding to the ve different positions to be occupied by the lever 43. The latch 55 is provided with a detent 53 movable into engagement with one of the notches |52 in any position to which the lever 4D is moved.

The latch plate 53 diiers from the latch plate 54 in that it is` provided with only a single notch 64. The notch 54 is adapted to receive a detent 55 carried by the latch 55 when the lever 40 occupies its neutral position, as indicated by the center line 5| in Fig. 2. When the lever 40 is out of its neutral position, the detent $5 rides on the arcuate surface 6E of the latch plate 53,

maintaining the latch'55 in the position shown in Fig. 2.

The circuit for the power operating means comprising the electromagnets I9, 3| and ||9, |3| is provided with a control switch 61 having a pivotally mounted movable contact member 68. The movable contact member 68 is pro-vided with a spring (not shown) for biasing such contact to its closed position.

The latch 55 hasan actuating member 10 projecting inwardly therefrom for engagement with a roller 1| carried by the pivotally movable contact 88 when the latch 55 is in the position shown in Fig. 2. The member 10 is effective to maintain the movable Contact 58 in its open position against the action of the spring 69, thereby interrupting thev control circuit for the power means and rendering such power means inoperative.

Assuming the lever 4Z! to be in its neutral position as indicated by the center line 5|, it will be rst necessary to movethe push button 58 inwardly before the emergency operating lever 40 may be actuated. Movement of the push button 58 inwardly moves both of the latches 55 and 55 to their unlocked position, releasing the handle 4i for movement and at the same time actuating the contact 58 to render the power means comprising the electromagnets i9, I9 and 3|, |3| inoperative. Thereafter, upon movement of the handle 4B to any of its operating positions,l

the fdetent Lv65 riding Aon fthe surface 66 will be fet-l fective to lock fout and zprevent operation of the power means. Moreover, the release o'f kthe push button 558 :after movement yof the handle 4D to any Aof 'li-'ts Loperating positions vwill `permit the latch 56 to move under its spring bias ina countercloc'kwise viilirection to la position with the detent k6.3 in one -o'f the notches 1612, thus locking the handle 4D against movement `from such pos'itfion. Upon 're'turnof the handle 4|) to its neutral position both of the 'detents 63 and '65 will move intoengagemen't 'witihnotches 62 and `64 to lock the handle f4!) against movement and the movable contact i613 will be closed by its spring bias `'to render "the `automatic or electromagnetic power means operative.

In Fig. f5, there is vshown amodi'cation adapt-y ing the principles of this invention to bus transfers employing a different type of Acontactor mechanism. In the :showing of Fig. 1, vit Lwill be recalled that the movable contacts |I are -rotatable to and vfrom their closed position. The upper and lower-switch :units .AandB of Fig. 5 are different fi-n that the movable -contacts are actuable by a 'so-called `rcl'apper type armature. However, the number -of elements andthe functions are substantially the same and like numerals have 'been employed "to designate elements functioning inthe same manner fas the elements designated 4by such 'numerals in t'h'e showing of Figs. 1 through il. Y'In View ofthe foregoing, Vit is believed suili'cient to point lout that -the armature 2'0 l(fl-2U) 'is connected to a bracket 12 |12) mounted ior pivotal 'movement about a pivot 13 (173'). The bracket carries the `movable 'contacts (not shown) by which the closing and opening of 'the 'switch units A 'and B are controlled. In addition, the bracket carries rollers '14 (|14) and 15 (115) for 'a purpose 'to be described. The latch members 1E 'and |16 in Fig. 5 function 'similarly 'to the latches 25 and |25 of Fig. 2 and are mounted "for pivotal movement about pivots 11 and 111, respectively. Springs 18 (|18) are provided :for biasing the latches to their closed position. The vmovable contact carrying 'bracket 1,2

(|12) has a gravity bias to its open position, a1-.

though it 'will be apparent that a spring bias could 'also be provided,

In the showing of Fig. 5, the switch unit A is illustrated as being in 'its closed position. In automatic operation to open the switch A and close the "switch B v'in the showing of Fig. 5, the electromagnet 3| is first operated to trip the latch 15E to `move the notch 19 from engagement with fthe Vroller 1'4 'to permit the bias of the bracket "t2 to move the switch unit A to its open position. Thereafter, energization of electromagnet ll ill will actuate the 'bracket '|12 to close the Aswitch unit B. Upon movement ofthe bracket '|112 toits closed position, the latch |16 will be moved by fits bias to latching vposition with the notch |19 Apositioned underneath the roller |14, preventing movement of the bracket |12 to its' open position. K

"In this showing, 'the lever 4D -`is mounted 'for pivotal movement about a shaft '80 and pivotal movement of the lever lll to its various operating positions is `effective to impart similar movement to fa lever 8f! carried by the shaft 8D through a resilient lost motion connection indicated fas a whole lby the numeral `#32. The lever 81| has one end thereof pivotally connected to an operating member `8'3 and has its other end pivotally connected to la J-shaped operating membei 8l. The operating member 83 is adapted to operate the .switch unit A :and the 1:operating member 84 lis v'adapted 'to operate "the switch unit B.

The member 83 is provided 'with 'a slot '85 engageable with the `pivot bushing 11 for guiding .the member 8'3 in its vertical movement. The

` carries Ya roller yS1 for 'operating the latch t5 in n s. L.)

amanner to be described.

The `l-shaped operating member 81| is guided in .its vertical movement by a pin "88 riding vin a slot 89 'formed in 'a stationary member 90. The base portion f9! ofthe QJ-shaped lever 84 is 'adapt` ed to fengage with the .roller |15 'in moving the lower switch `unitB to 'its closed position. `In addition, the 'upwardly projecting arm 92 of "the member B4 carries a latch operating roller 93.

The operation of the switch units A and Bin Fig. '5 :as'the .lever 140 moves through .its operating positions iis the same as described in connection with the .showings fof Figs. Vl. `and 2. Accordingly, the operation of the modification of Fig. 5 will be sufciently apparent 'from .a description of the motion taking place iin vmovement of .the latch lever '4H from thepo'sition shown 'in 'full lines to the position shown in do'tJan'd-dashlin'es. As the lever 4D is moved 'from 'the position shown in fullv lines to its neutral position as indicated by the center line 5|, no l"action takes place other than `a lowering of 'the .member 85 and a lifting of the lever 84. .As the lever "4U 'thereaftermoves tothe tripping "position, as indicated by the 'center line 52, the roller 81 will'engage the cammingmember 91| secured to the upper latchlto move thenotch 19 from underneath the "latch :roller 14 kto permit movement of the switch unit A to 'lits open position. vContinued lmovement ofthe lever 4D to its position as 'indicated in -d'oteand-dash lines, will engage fthe member '9| with the roller |15 'and effect movement of the roller l T5 'and its 'supporting bracket |12 in an upward direction to close the switch unit iB.

'The interlocking control of 'the 'automatic and emergency` operating means `of Fig. '5 is essentially the same as that shown "in Fig. l2. lHowever, it will '.benoted that the latch plates 53 and 54fare 'carried directly by the handle 540 and moved therewith about the pivot .shaft BD. The *latching members 55 and A5t carrying the detents '63 and '62| are mounted on a support 'Q5 for 'pivotal movement with respect thereto. The interlock'- ing parts operable by Athe push lbutton 58 and cooperatingwith the latch plates 53 and 54 function in the same `manner 'as vdescribed-'in the embodiment shown in Figs. 1 and 2.

We claim as our invention:

l. In "combination, a control `having a pair 'of electric "switches respectively movable between open and' closed positions and 'having 'a bias ior movement 'toward "open position, a latch assol ciated with each of vsaid switches Tor locking its associated switchin closed 'position 'and having 'a bias for movement Atoward locking position; "and means for operating ysaid lswitches comprising a common control member, separate linksconnecting said' member to each of `said switches, each of said links `being operable upon :movement in one kdirection to 'move one of said switclu-z's against its bias to closed position fandupon tmovenl'en't in an opposite direction -to .move the :latch associated with'l 'such switchl against its bias tov unlocking position to release such switch for movement by its bias to open position, said links being operable upon movement of said member in one direction to nrst unlatch one of said switches and thereafter close the other of said switches, and upon movement in an opposite direction to first unlatch said other switch and thereafter close said one switch.

2. The combination of claim 1 wherein said operating member is movable to switch operating positions from an intermediate neutral position together with power-operated means for operating said latches and switches, a control means for rendering said power-operated means inoperative, and an interlock disposed between said control means and said operating member so as to be eiiectivewhen said member is in said neutral position whereby said power-operated means are rendered operative, and said interlock being actuable to release said member for movementv from its neutral position and to cause said control means to render said power-operated means inoperative.

3. In combination, a control having a pair of electric switches respectively movable between -open and closed positions and having a bias to one of saidpositions, a latch associated with each of said switches movable into locking engagement with its associated switch upon movement of such switch to its other position, power-operated actuating means operable to trip one of said latches to release its associated switch for movement under its bias to said one position and to move the other of said switches against its bias to its other position in such manner that only one of said switches is closed at any given time, and emergency means for operating said switches and latches independently of said actuating means comprising a single manually operable control member, and means connecting said control member with each of said switches and their associated latches effective upon movement of said control member in one direction to trip one of said latches and move one of said switches against its bias, and upon movement in an opposite direction to trip the other of said latches and to move the other of said switches against its bias, in such manner that only one of said switches is closed at any given time.

4. In combination, a control having a pair of electric switches, and lpower-operated means for operating said switches, an emergency operating member, means interconnecting said member with both of said switches to render said member operable to selectively close one of said switches independently of said power means, and locking means controlled by said member and connected with said power-operated means for rendering the latter ineiective in dependence upon said member being in operative condition.

5. In combination, a control having a pair of electric switches, and power-operated means :for operating said switches, control means for rendering said power means inoperative, and an emergency operating member for operating said switches independently of said power-operated means, said control means being interconnected with said member for rendering said power means inoperative upon operation of said member.

6. In combination, a control having a pair of electric switches, and power-operated means for operating said switches. control means for rendering said power means inoperative, an emergency operating member, means interconnecting said member with both of said switches to render said member operable to selectively close one oi said switches independently of said power-operated means, and means interconnecting said member'with said control means for operating said control means upon operation of said member to'close one of said switches.

7. In combination, a control having a pair of electric switches and automatic magnetic actuating means connected to said switches for operating the same, a common movable operating member,

' in dependence upon said member being in operative position.

8. In combination, a control having a pair of electric switches and electrically operated actu.-y ating means connected to said switchesfor operating said switches automatically, a control switch'for rendering said actuating means inoperative, an operating member, means connecting said member with both of said switches to render said member operable to selectively close one of said switches independently of said means, andmeans interlocking said control switch with said .member for maintaining said actuating means inoperative during operation of said member.

9. In combination, a control having a pair of electric switches, and power-operated actuating means for operating said switches, control means for rendering said actuating means inoperative, a common operating member having connections with both of said switches and operative upon movement in opposite directions from a given position to selectively operate either of said switches independently of said power means, and latch means for locking said member in said given position, said latch means being effective upon operation thereof to release said member to operate said control means to render said actuating means inoperative.

10. In combination, a control having a pair of electric switches, and power-operated actuating means for operating said switches, control means for rendering said actuating means inoperative, a common operating member having connections with both of said switches and operative inde pendently of said actuating means upon movement in opposite directions from a given position to selectively operate either of said switches, a latchY plate secured to and movable with said member, a latch movable into locking engagement with said plate for locking said member in said given position, and means operative upon movement of said latch out of locking engagement to operate said control means to render said actuating means inoperative.

11. In combination, a control having a pair of electric switches, a latch for each of said switches movable to locking position upon movement of its associated switch to closed position, an emergency operating member, means interconnecting said member with said switches and latches for rendering said member operative to selectively operate one of said switches and its associated latch independently of said devices, and electric actuating devices associated with said latches respectively toy operate said switches automatically,.r and electric contact, means. controlled by said. member and connected withy said electric actuating: de,- vices for rendering the latter ineffective: when saidv member is in operative. condition.v

12. In combination, a. control having. a pair of electric switches, a latch for each. of said switches movable to locking. position upon movement of its; associated switch to closed position,. and power-operated. actuating means for operating said. latches and switches, control means, for rendering said actuating means. inoperative, an operatingf member operatively related. to said switches and latches andv effective independently of. said actuating means forr operating a selected one of said switches and; its associated latch, and means operable to. actuate. said control means upon movement of. said member to close4r one: of. said switches.

13.v In combination, av control having a pair of electricswitches, a. latch for each of said switches movable to locking position upon movement of its associated switch to closed position, and poweroperated actuating means for operating said` latches and switches, control means for ren.- dering said actuating. meansl inoperative, an: op-

erating member having. connections with said switches and latches operative independently of said actuating means upon movement in. opposite directions from at given. position toy selectively operate.A either of said switches.,. and latch means for. locking said member in said given. position, said.- latch means being eiective, upon operation .thereo to, release said member for operating said control means to render said actuating means inoperative.

1:4. In: combination; a. control having; a; pair-of electri switches; and; powereoperated actuating means for` operating said switches. a common control member having connections 'with said switches for operati-ng: thev same. independently of said actuatingl means', saidl control. member having; a neutral positiont and being movable therefrom in opposite directions to operating. p0-

'siti-ons'., and latching control; means operative when said. member is` in its: neutral; position to locksaid member against movement, said control means being connected with said. actuating means so1 as toy render said' actuating means operative when said. member is: iny its neutral. position and inoperative when. said .member isr moved. out. of neutral position..

15. In combination-, an electric switch movable between. open and closed, positions. and having a bias. toward one of said positions, a latching memberl movable between positions locking and FERDINAND C. IGLEHARI. BRUNO. L. ULLRICH. 

